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What are some human diseases caused by bacteria and what are their respective modes of transmission?

The main human bacterial infections transmitted by respiratory secretions (sneezes, cough) and saliva drops are: bacterial pneumonias, tuberculosis, whooping cough (pertussis), diphtheria, bacterial meningitis. Main bacterial diseases transmitted by blood or sexual contact are: gonorrhea, syphilis. Main bacterial diseases transmitted by animal vectors are: bubonic plague, endemic typhus, leptospirosis. Some bacterial diseases transmitted through fecal-oral route and contaminated food are: cholera, typhoid fever. Other important bacterial infections: Hansen's disease, possibly transmitted by saliva drops and contact with injured skin and mucosae; trachoma, eye disease transmitted by ocular secretions; tetanus, transmitted when the etiologic agent enters the body through skin wounds.

What is tuberculosis? How is the disease transmitted? Is there treatment for tuberculosis?

Tuberculosis is a disease caused by the Mycobacterium tuberculosis, a bacteria that attacks other organs of the body but mainly the lungs leading to respiratory insufficiency. Before 1940, tuberculosis have already been the main cause of death in the USA and Europe. The disease can remain latent, without manifestation for several years and even throughout the life.

Tuberculosis is highly contagious, transmitted by air route through sneezes and coughs from a person with the active disease. It is common the transmission between members of a same family or even in work environments. The disease today has treatment with efficient antibiotics. Generally, the patient receives for several months three different drugs until complete healing. There are however some strains of multiresistant TB bacteria that emerged by mutation and natural selection due to the intense use of antibiotic drugs mainly in hospitals and treatment facilities; in these cases the treatment is more difficult.

Is there vaccine against tuberculosis?

The vaccine against tuberculosis is called BCG (bacillus Calmette-Guérin). BCG is not used in some countries where tuberculosis is not so prevalent because it can distort later diagnostic studies of the disease; in other countries, like Brazil, it is obligatory for children. The vaccine is made of attenuated TB bacteria.